Enhanced corrosion resistance of micro-arc oxidation coated magnesium alloy by superhydrophobic Mg-Al layered double hydroxide coating  

镁合金微弧氧化陶瓷层表面超疏水Mg-Al层状双金属氢氧化物涂层的耐蚀性（英文）

作　　者：Zhi-hu WANG Ju-mei ZHANG Yan LI Li-jing BAI Guo-jun ZHANG 王志虎;张菊梅;李妍;白力静;张国君(西安理工大学材料科学与工程学院,西安710048;西安科技大学材料科学与工程学院,西安710054)

机构地区：[1]School of Materials Science and Engineering,Xi’an University of Technology,Xi’an 710048,China [2]School of Materials Science and Engineering,Xi’an University of Science and Technology,Xi’an 710054,China

出　　处：《Transactions of Nonferrous Metals Society of China》2019年第10期2066-2077,共12页中国有色金属学报（英文版）

基　　金：Project(17JS083) supported by the Key Laboratory Program of Shaanxi Education Department,China;Project(2016JZ018) supported by the Key Program of Natural Science Research of Shaanxi Province,China;Project(51701162) supported by the National Natural Science Foundation of China

摘　　要：To further enhance the corrosion resistance of the porous micro-arc oxidation(MAO) ceramic layers on AZ31 magnesium alloy, superhydrophobic Mg-Al layered double hydroxide(LDH) coating was fabricated on MAO-coated AZ31 alloy by using in-situ growth method followed by surface modification with stearic acid. The characteristics of different coatings were investigated by XRD, SEM and EDS. The effect of the hydrothermal treatment time on the formation of the LDH coatings was studied. The results demonstrated that the micro-pores and cracks of MAO coating were gradually sealed via in-situ growing LDH with prolonging hydrothermal treating time. Electrochemical measurement displayed that the lowest corrosion current density, the most positive corrosion potential and the highest impedance modulus were observed for superhydrophobic LDH/MAO coating compared with those of MAO coating and LDH/MAO coating. Immersion experiment proved that the superhydrophobic LDH/MAO coating with the active anti-corrosion capability significantly enhanced the long-term corrosion protection for MAO coated alloy.为进一步提高镁合金微弧氧化多孔陶瓷层的耐蚀性,采用原位水热法及硬脂酸表面改性方法,在陶瓷层表面制备超疏水镁铝层状双金属氢氧化物(Mg-Al LDH)涂层。采用X射线衍射议、扫描电子显微镜及能谱仪研究涂层的结构、形貌及成分,研究水热处理时间对Mg-Al LDH膜形成的影响。结果表明,随着水热处理时间的延长,原位生长的Mg-AlLDH将MAO陶瓷层表面的微孔和微裂纹逐渐闭合。电化学测试结果表明,与MAO陶瓷层和LDH/MAO涂层相比,超疏水LDH/MAO复合涂层具有最低的腐蚀电流密度、最正的腐蚀电位以及最大的阻抗模量;浸泡实验结果证明,具有主动防护性能的超疏水LDH/MAO涂层可以显著提高MAO陶瓷层的长期耐腐蚀性能。

关 键 词：magnesium alloy micro-arc oxidation layered double hydroxide SUPERHYDROPHOBICITY corrosion resistance 

分 类 号：TG174.4[金属学及工艺—金属表面处理]